1. Field of the Invention
The present invention generally relates to L-clamps. Particularly, the present invention relates to a sliding rack L-clamp.
2. Description of the Prior Art
A standard L-clamp or bar clamp has a straight bar attached to a fixed arm. A sliding arm slides along the straight bar and the outer end of the sliding arm comprises a threaded screw which comprises a handle on one end and a pad on the other end. When the handle is turned, the pad engages an object being clamped between the pad on the end of the threaded screw and the pad on the end of the fixed arm. However, as the screw is turned the pad at the end of the screw rotates generally causing marring of the object or walking movement or deflection of the screw on the object being clamped.
The related prior art includes U.S. Pat. No. 6,367,790 (2002, Ocklenburg et al.) which discloses a sliding arm L-clamp comprising a bar, an elbow, and an arm. The movable arm extends from the bar, slides along the bar, and has an outer end which is threaded to a spindle carrying a handle or crank at one end and a first abutment pad at the opposite end. The fixed arm carries at its outer end a second abutment pad parallel with the first abutment pad. However, as the spindle turns, the abutment pad turns creating the possibility of marring a workpiece being held in the L-clamp.
U.S. Pat. No. 5,893,553 (1999, Pinkous) discloses a C-shaped clamp having a pad that does not rotate when an elongated threaded rod with an extendible thread surface is screwed toward a ball jointed pad on the opposite end of the C-clamp device. The elongated threaded rod is attached to the top of a pad bracket and a bar means attaches to an end of the pad bracket perpendicular to the rod. The blocking rod prevents the pad bracket from rotating. However, this design does not support the exterior spindle and still allows for pad and spindle rotation, albeit limited.
U.S. Pat. No. 5,405,124 (1995, Mayer) discloses a sliding arm C-shaped clamp bow with a nonrotating pad or clamping body. A clamping spindle is threaded through a spindle nut at one end of the bow. The contact surface of the end of the spindle is secured within the clamping body so that as the contact surface of the spindle rotates within the clamping body, the surface clamping element remains stationary. The clamping body extends from the guide section along the clamp bow. However, this is a C-shaped clamp with a spindle and not an L-clamp and the exposed spindle is unsupported by an exterior housing.
Therefore, what is needed is a sliding arm L-clamp that does not rotate when being tightened. What is further needed is an L-clamp that prevents marring of a workpiece, walking movement, or deflection of a screw on a workpiece when tightening the L-clamp on a workpiece. What is still further needed is an L-clamp that provides fast clamping of a workpiece.